Reusable inventory: 3D tool rack (notebook + phone)

A tool-driven inventory overlay — a three.js rack you cycle with ◀ ▶ and
open with USE. Registry-based (not tied to a level type) so new tools just
add a model + component. Reuses the phone's 3D model; notebook is a blocky
placeholder tool. Dev route /?inventory=1; drop <Inventory/> into the navbar
after the merges.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/phone.tsx

@@ -11,7 +11,7 @@ import * as THREE from 'three'
 // flag requirements come from the story graph (see the "mobile" gate discussion).
 const SCREEN_RECT = { top: 9, left: 25, width: 50, height: 30 } // % of the stage
 
-const CLOSED_ANGLE = 3.12 // hinge rotation.x when shut (~179°: lid folds over the keypad)
+export const CLOSED_ANGLE = 3.12 // hinge rotation.x when shut (~179°: lid folds over the keypad)
 const OPEN_ANGLE = 0 // lid stands up, coplanar with the keypad, facing camera
 
 // ---- placeholder telephony audio (to be replaced by recorded assets) ----------
@@ -46,7 +46,7 @@ const sfx = {
 
 type Built = { group: THREE.Group; hinge: THREE.Group; keys: THREE.Mesh[] }
 
-function buildPhone(): Built {
+export function buildPhone(): Built {
   const group = new THREE.Group()
   const keys: THREE.Mesh[] = []